Power transfer apparatus, power transmission apparatus, power reception apparatus, and power transfer system

ABSTRACT

Provided is a power transfer apparatus capable of effectively cooling heat generated by wireless power transfer.The power transfer apparatus is provided with: a power transmission coil TC for performing wireless power transfer; and a heat-dissipating plate CBT for cooling the power transmission coil TC, the heat-dissipating plate CBT comprising heat-dissipating members CB0 or the like which are divided by gaps GP along the radial direction of a winding plane of a copper thin-film wire constituting the power transmission coil TC.

CROSS-REFERENCE TO RELATED APPLICATION

This is a Continuation of application Ser. No. 17/271,846 filed Feb. 26,2021, which in turn is a PCT National Stage Application ofPCT/JP2019/034251 filed Aug. 30, 2019, which claims the benefit ofJapanese Patent Application No. 2018-161930 filed Aug. 30, 2018. Thedisclosure of the prior applications is hereby incorporated by referenceherein in its entirety.

TECHNICAL FIELD

The present invention belongs to a technical field of a power transferapparatus, a power transmission apparatus, a power reception apparatus,and a power transfer system. More specifically, the present inventionbelongs to a technical field of a power transfer apparatus fornon-contact type power transfer, a non-contact type power transmissionapparatus and a non-contact type power reception apparatus using thepower transfer apparatus, and a non-contact type power transfer system.

BACKGROUND ART

Recently, for example, an electric vehicle on which a storage batteryincluding a lithium ion battery or the like is mounted has been inwidespread use. Such an electric vehicle is moved by driving a motorwith power stored in the storage battery, and thus, efficient charge forthe storage battery has been required. Therefore, as a method forcharging the storage battery mounted on the electric vehicle withoutphysically connecting a charge plug or the like with respect to theelectric vehicle, a research on using a power reception coil and a powertransmission coil that face each other and are separated from eachother, a so-called wireless power transfer has been conducted. Ingeneral, examples of the current wireless power transfer method includean electric field coupling method, an electromagnetic induction method,a magnetic field resonance method, and the like. In the case ofcomparing such methods, for example, from the viewpoint of a usablefrequency, a position freedom degree in each of a horizontal directionand a perpendicular direction, a transfer efficiency, and the like, anelectric field coupling method using a capacitor or a magnetic fieldresonance method using a coil has been a promising entry for a wirelesspower transfer method for charging the storage battery mounted on theelectric vehicle, and the research and development thereof has also beenactively conducted.

On the other hand, in the wireless power transfer as described above, itis necessary to charge a high-capacity storage battery preferably for ashort period of time, and thus, in general, power to be transmitted andreceived increases. Then, in order to increase the power to betransmitted and received, it is necessary to allow a large current toflow through both of the power reception coil described above and thepower transmission coil described above, and large Joule heat isgenerated in both of the power reception coil and the power transmissioncoil due to the large current. Accordingly, in particular, in the powerreception coil that is mounted on the electric vehicle, it is requiredto efficiently cool the power reception coil by diffusing the generatedJoule heat. Then, examples of the literature of the prior art in whichthe cooling of the power reception coil and the power transmission coilis disclosed include Patent Document 1 described below. In PatentDocument 1, a technology relevant to a heat release member that performsheat release by propagating heat generated in a coil through a circuitincluding a ferrite core is disclosed.

CITATION LIST Patent Document

-   Patent Document 1: WO 2013/183665 A (FIG. 1 and the like)

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

However, the technology disclosed in Patent Literature 1 described aboveis applied only to a so-called solenoid type coil, and the heat releasemember that can be applied to a coil such as the power reception coildescribed above widely used in the electric vehicle described above, amobile apparatus, or the like is not disclosed nor indicated.Accordingly, the technology described in Patent Literature 1 describedabove does not contribute to the cooling of the power reception coilused in the electric vehicle described above or the like. Further,necessary charge can be performed with the transfer of small power byimproving a transfer efficiency as the coil, and thus, the flow of alarge current is suppressed, and as a result thereof, the generation ofJoule heat is also suppressed.

Therefore, the present invention has been made in consideration of therequests and the problems described above, and an example of an objectthereof is to provide a power transfer apparatus that is capable ofimproving a transfer efficiency in a non-contact type power transferwhile effectively cooling heat that is generated by the power transfer,a non-contact type power transmission apparatus and a power receptionapparatus using the power transfer apparatus, and a power transfersystem.

Means for Solving the Problem

In order to solve the above-mentioned problem, the invention describedin claim 1 comprises: a transfer means that performs a non-contact typepower transfer; and a metallic heat release means that cools thetransfer means, wherein the transfer means includes a coil in which awinding wire is wound a plurality of times, and the heat release meansis formed in a range including a range facing a region of the coilexcluding an inside region from a position of the winding wire woundaround an innermost circumference and a range facing an outside regionfrom the position of the winding wire wound around an outermostcircumference, in a plane parallel to a winding surface of the windingwire, and includes heat release members divided by one or a plurality ofgaps along a radial direction of the winding surface.

According to the invention described in claim 1, a metallic heat releasemeans includes the heat release members divided by one or a plurality ofgaps along the radial direction of the winding surface of the windingwire configuring the coil, and thus, a current due to an electromagneticwave that is generated from a transfer means by the power transfer isdivided, and therefore, a transfer efficiency as the power transferapparatus can also be improved while effectively cooling the transfermeans from heat that is generated due to the flow of the current.

In addition, the transfer means includes the coil in which the windingwire is wound a plurality of times, the gap of the heat release means isa gap that is formed along the radial direction of the winding surface,in the plane of the heat release means parallel to the winding surfaceof the winding wire configuring the coil, and the heat release meansincludes one or a plurality of heat release members that are divided bythe gaps, and thus, the transfer efficiency as the power transferapparatus can be improved while efficiently cooling the transfer means.

Further, the heat release member is formed in the range facing theregion of the coil excluding the inside region from the position of thewinding wire wound around the innermost circumference, and thus, thetransfer efficiency as the power transfer apparatus can be improvedwhile effectively cooling the coil by suppressing the generation of thecurrent in the heat release means due to the electromagnetic wave thatis generated in the inside region.

In addition, the heat release member is formed in the range facing theregion of the coil in which the winding wire is wound, and the rangefacing the outside region from the position of the winding wire woundaround the outermost circumference, and thus, the transfer means can beefficiently cooled by increasing the size as the heat release member,that is, as the heat release means.

In order to solve the above-mentioned problem, the invention describedin claim 2 and according to claim 1 further comprises: a thermallyconductive resin layer between the transfer means and the heat releasemeans.

According to the invention described in claim 2, the thermallyconductive resin layer is further provided between the transfer meansand the heat release means, and thus, adhesiveness between the transfermeans and the heat release means can be increased, and the transfermeans can be efficiently cooled while avoiding the risk of dischargefrom the transfer means, in addition to the function of the inventiondescribed in claim 1.

In order to solve the above-mentioned problem, the invention describedin claim 3 and according to claim 1 or 2 further comprises: a shieldingmeans that is disposed on a side opposite to a power transmission sideof the transfer means at the time of power transmission or a sideopposite to a power reception side of the transfer means at the time ofpower reception when seen from a position of the transfer means and theheat release means, and shields an electromagnetic wave generated by thepower transfer; and a magnetic means that is disposed between thetransfer means and the heat release means, and the shielding means, andincludes a magnetic body, wherein an area of the shielding means and themagnetic means in a plane perpendicular to a straight line toward theshielding means and the magnetic means from the position of the transfermeans is greater than or equal to an area of the transfer means in theplane.

According to the invention described in claim 3, a shielding means thatis disposed on a side opposite to the power transmission side or a sideopposite to the power reception side when seen from the position of thetransfer means and the heat release means, and a magnetic means that isdisposed between the transfer means and the heat release means, and theshielding means are further provided, and the area of the shieldingmeans and the magnetic means in the plane perpendicular to the straightline toward the shielding means and the magnetic means from the positionof the transfer means is greater than or equal to the area of thetransfer means in the plane, and thus, the transfer efficiency as thepower transfer apparatus can be improved while effectively cooling thetransfer means, and a protection target to be protected can beeffectively protected from the electromagnetic wave that is generated bythe power transfer, in addition to the function of the inventiondescribed in claim 1 or 2.

In order to solve the above-mentioned problem, the invention describedin claim 4 is the power transfer apparatus according to claim 3, whereinthe straight line is a perpendicular line that is erected in a directiontoward the shielding means and the magnetic means with a center of thecoil as a foot, and an area of a surface perpendicular to theperpendicular line of the shielding means and the magnetic means thatare respectively in the shape of a plate is greater than or equal to anarea of the winding surface of the winding wire in the coil.

According to the invention described in claim 4, the area of the surfaceperpendicular to the perpendicular line of the shielding means and themagnetic means that are in the shape of a plate, in which theperpendicular line is erected in the direction toward the shieldingmeans and the magnetic means with the center of the coil as the foot, isgreater than or equal to the area of the winding surface of the windingwire in the coil, and thus, the transfer efficiency as the powertransfer apparatus can be improved while cooling the transfer means, andthe protection target can be effectively protected from theelectromagnetic wave that is generated by the power transfer, inaddition to the function of the invention described in claim 3.

In order to solve the above-mentioned problem, the invention describedin claim 5 is the power transfer apparatus according to claim 4, whereinthe transfer means includes a first coil that performs the powertransmission or the power reception of power, as the power transfer, anda second coil stacked on the first coil in which power to be subjectedto the power transmission is supplied at the time of the powertransmission, and power to be subjected to the power reception is outputat the time of the power reception.

According to the invention described in claim 5, the transfer meansincludes the first coil and the second coil concentrically stacked onthe first coil, and thus, the transfer efficiency can be improved whilecooling the transfer means, and the protection target can be effectivelyprotected from the electromagnetic wave, in addition to the function ofthe invention described in claim 4.

In order to solve the above-mentioned problem, the invention describedin claim 6 is the power transfer apparatus according to claim 5, whereinthe first coil includes an out-in winding wire that is wound toward aninner circumference side from an outer circumference side of the firstcoil, and an in-out winding wire that is wound in a winding directionopposite to the out-in winding wire toward the outer circumference sidefrom the inner circumference side of the first coil, and in the firstcoil, the out-in winding wire and the in-out winding wire are stackedsuch that a winding position of the out-in winding wire is coincidentwith a winding position of the in-out winding wire.

According to the invention described in claim 6, the first coil includesthe out-in winding wire and the in-out winding wire, and in the firstcoil, the out-in winding wire overlaps with the in-out winding wire byinterposing an insulating portion therebetween such that the windingcenter of the out-in winding wire is coincident with the winding centerof the in-out winding wire, and thus, the transfer efficiency can beimproved while cooling the transfer means and reducing a resonancefrequency, and the protection target can be effectively protected fromthe electromagnetic wave, in addition to the function of the inventiondescribed in claim 5.

In order to solve the above-mentioned problem, the invention describedin claim 7 is the power transfer apparatus according to claim 5 or 6,wherein in the second coil, a winding wire is wound a plurality oftimes.

According to the invention described in claim 7, in the second coil, thewinding wire is wound a plurality of times, and thus, a transferefficiency of power can be further improved, in addition to the functionof the invention described in claim 5 or 6.

In order to solve the above-mentioned problem, the invention describedin claim 8 is the power transfer apparatus according to any one ofclaims 1 to 7 and further comprises a second heat release means that isthermally connected to and is electrically insulated from any one of theheat release members, on an outer edge of the heat release means.

According to the invention described in claim 8, the second heat releasemeans that is thermally connected to and is electrically insulated fromany one of the heat release members, on the outer edge of the heatrelease means, is further provided, and thus, a cooling effect as thepower transfer apparatus can be further increased, in addition to thefunction of the invention described in any one of claims 1 to 7.

In order to solve the above-mentioned problem, the invention describedin claim 9 is a power transmission apparatus provided in a powertransfer system that includes the power transmission apparatus and apower reception apparatus separated from the power transmissionapparatus, and transfers power to the power reception apparatus from thepower transmission apparatus in a non-contact manner, the powertransmission apparatus comprises: the power transfer apparatus accordingto any one of claims 1 to 8; and an output means that outputs power tobe transferred to the transfer means of the power transfer apparatus.

In order to solve the above-mentioned problem, the invention describedin claim 10 is a power reception apparatus provided in a power transfersystem that includes a power transmission apparatus and the powerreception apparatus separated from the power transmission apparatus, andtransfers power to the power reception apparatus from the powertransmission apparatus in a non-contact manner, the power receptionapparatus comprises: the power transfer apparatus according to any oneof claims 1 to 8; and an input means that is connected to the transfermeans of the power transfer apparatus.

In order to solve the above-mentioned problem, the invention describedin claim 11 comprises: the power transmission apparatus according toclaim 9; and a power reception apparatus that is separated from thepower transmission apparatus, is disposed to face the transfer means,and receives power transmitted from the power transmission apparatus.

In order to solve the above-mentioned problem, the invention describedin claim 12 comprises: a power transmission apparatus; and the powerreception apparatus according to claim 10 that is separated from thepower transmission apparatus and receives power transmitted from thepower transmission apparatus in which the transfer means is disposed toface the power transmission apparatus.

According to the invention described in any one of claims 9 to 12, thepower transmission apparatus or the power reception apparatus includesthe power transfer apparatus described in any one of claims 1 to 8, andthus, as the power transfer system, the transfer efficiency as the powertransfer apparatus can also be improved while effectively cooling thetransfer means.

Effects of the Invention

According to the invention, a metallic heat release means includes theheat release members divided by one or a plurality of gaps along theradial direction of the winding surface of the winding wire configuringthe coil.

Therefore, a current due to an electromagnetic wave that is generatedfrom a transfer means by the power transfer is divided, and therefore, atransfer efficiency as the power transfer apparatus can also be improvedwhile effectively cooling the transfer means from heat that is generateddue to the flow of the current.

In addition, the transfer means includes the coil in which the windingwire is wound a plurality of times, the gap of the heat release means isa gap that is formed along the radial direction of the winding surface,in the plane of the heat release means parallel to the winding surfaceof the winding wire configuring the coil, and the heat release meansincludes one or a plurality of heat release members that are divided bythe gaps, and thus, the transfer efficiency as the power transferapparatus can be improved while efficiently cooling the transfer means.

Further, the heat release member is formed in the range facing theregion of the coil excluding the inside region from the position of thewinding wire wound around the innermost circumference, and thus, thetransfer efficiency as the power transfer apparatus can be improvedwhile effectively cooling the coil by suppressing the generation of thecurrent in the heat release means due to the electromagnetic wave thatis generated in the inside region.

In addition, the heat release member is formed in the range facing theregion of the coil in which the winding wire is wound, and the rangefacing the outside region from the position of the winding wire woundaround the outermost circumference, and thus, the transfer means can beefficiently cooled by increasing the size as the heat release member,that is, as the heat release means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block figure illustrating an outline configuration of apower transfer system of an embodiment.

FIG. 2 is a perspective view conceptually illustrating a structure ofthe power transfer system of the embodiment.

FIG. 3 is a plan view (i) illustrating a structure of a powertransmission coil of the embodiment.

FIG. 4 is a plan view (ii) illustrating the structure of the powertransmission coil of the embodiment.

FIG. 5 is a plan view (iii) illustrating the structure of the powertransmission coil of the embodiment.

FIG. 6 is a partial sectional view illustrating the structure of thepower transmission coil of the embodiment.

FIG. 7A is a plan view illustrating a structure of a heat release plateof the embodiment.

FIG. 7B is a side view of the power transmission coil including the heatrelease plate of the embodiment.

FIG. 8 is a plan view illustrating a structure of a heat release plateof a first modification embodiment.

FIG. 9 is a plan view illustrating a structure of a heat release plateof a second modification embodiment.

FIG. 10 is a plan view illustrating a structure of a heat release plateof a third modification embodiment.

FIG. 11 is a plan view illustrating a structure of a heat release plateof a fourth modification embodiment.

FIG. 12 is a plan view illustrating a structure of a heat release plateof a fifth modification embodiment.

FIG. 13 is a figure illustrating a state of a leaked magnetic field dueto the structure of the power transfer system of the embodiment.

FIG. 14 is a plan view illustrating a structure of a heat release plateof a first comparative example.

FIG. 15A is a figure illustrating a generation status of an eddy currentor the like in the heat release plate of the embodiment, each of themodification embodiments, and the like.

FIG. 15B is a figure illustrating the generation status of the eddycurrent or the like in the heat release plate of the third modificationembodiment.

FIG. 15C is a figure illustrating the generation status of the eddycurrent or the like in the heat release plate of the fourth modificationembodiment.

FIG. 15D is a figure illustrating the generation status of the eddycurrent or the like in the heat release plate of the fifth modificationembodiment.

FIG. 15E is a figure illustrating the generation status of the eddycurrent or the like in the heat release plate of the third comparativeexample.

FIG. 16 is a sectional conceptual figure illustrating a configuration ofa heat release plate or the like in other embodiments.

MODES FOR CARRYING OUT THE INVENTION

Next, modes for carrying out the present invention will be described onthe basis of the drawings. Note that, an embodiment and eachmodification embodiment described below are embodiments in the case ofapplying the present invention to a power transfer system in which powerfor charging a rechargeable battery that is mounted on an electricvehicle is transmitted to the electric vehicle including therechargeable battery in a non-contact manner by a magnetic fieldresonance method, respectively.

Here, the power transfer system using the magnetic field resonancemethod of the embodiment and each of the modification embodimentsincludes a power transmission coil that transmits power, and a powerreception coil that is disposed separated from the power transmissioncoil to be opposite to each other (that is, to face each other) andreceives power transmitted from the power transmission coil. Then, thepower transmission coil described above has a configuration in which apower transmission loop coil described below and a power transmissionopen coil described below are respectively stacked. In addition, thepower reception coil described above has a configuration in which apower reception open coil described below and a power reception loopcoil described below are respectively stacked.

(I) Embodiment

First, an embodiment of the present invention will be described by usingFIG. 1 to FIG. 7B.

(i) Overall Configuration and Operation of Power Transfer System ofEmbodiment

First, the overall configuration and the operation of a power transfersystem of an embodiment will be described by using FIG. 1 and FIG. 2 .Note that, FIG. 1 is a block figure illustrating the outlineconfiguration of the power transfer system of the embodiment, and FIG. 2is a perspective view conceptually illustrating the structure of thepower transfer system.

As illustrated in the block figure of FIG. 1 , a power transfer system Sof the embodiment includes a power reception apparatus R including apower reception unit RV and a power reception coil RC described above,and a power transmission apparatus T including a power transmission unitTR and a power transmission coil TC described above. At this time, thepower reception apparatus R is mounted on the electric vehicle describedabove, and is connected to a storage battery mounted on the electricvehicle that is not illustrated. On the other hand, the powertransmission apparatus T is provided on the ground surface in a positionwhere the electric vehicle is moved or stops. Then, in a case where thestorage battery is charged, the electric vehicle is driven or stops suchthat the power reception coil RC of the power reception apparatus R andthe power transmission coil TC of the power transmission apparatus Tface each other. Note that, when the storage battery described above ischarged by the power transfer system S of the embodiment, power can betransferred to the power reception apparatus R mounted on the electricvehicle that stops from the power transmission apparatus T through thepower transmission coil TC of the power transmission apparatus Tprovided on the ground surface below the stopping position. In addition,power may be continuously transferred to the power reception apparatus Rmounted on the electric vehicle that is being moved from the powertransmission apparatus T through the power transmission coils TC of aplurality of power transmission apparatuses T provided in sections witha constant distance on the road where the electric vehicle is beingmoved. Then, the power transmission apparatus T described above or thepower reception apparatus R described above correspond to an example ofa “power transfer apparatus” of the present invention, the powertransmission coil and the power reception coil RC described abovecorrespond to an example of a “transfer means” of the present invention,the power transmission unit TR described above corresponds to an exampleof an “output means” of the present invention, and the power receptionunit RV described above corresponds to an example of an “input means” ofthe present invention. Further, in FIG. 1 , the power reception coil RCside of the power transmission coil TC corresponds to a “powertransmission side” of the power transmission coil TC, and the powertransmission coil TC side of the power reception coil RC corresponds toa “power reception side” of the power reception coil RC.

On the other hand, the power transmission coil TC described aboveincludes a power transmission loop coil TL and a power transmission opencoil TO. In addition, the power reception coil RC described aboveincludes a power reception open coil RO and a power reception loop coilRL. At this time, power to be transmitted is input into the powertransmission loop coil TL from the power transmission unit TR. Then, thepower transmission open coil TO is concentrically stacked on the powertransmission loop coil TL in which both ends thereof are an open end. Onthe other hand, the power reception open coil RO is disposed on thepower transmission open coil TO to face each other in which both endsthereof are an open end. Then, the power reception loop coil RL isconcentrically stacked on the power reception open coil RO in whichpower received from the power transmission coil TC by the magnetic fieldresonance method is output to the power reception unit RV. At this time,the power transmission open coil TO or the power reception open coil ROcorresponds to an example of a “first coil” of the present invention,and the power transmission loop coil TL or the power reception loop coilRL corresponds to an example of a “second coil” of the presentinvention.

In the configuration described above, the power transmission unit TR ofthe power transmission apparatus T, for example, outputs power to betransferred to the power reception apparatus R to the power transmissioncoil TC while complying with a law or the like such as a radio law in acountry where the power transfer system S is used. At this time, in thelaw or the like described above, for example, a leaked magnetic field isregulated to be less than or equal to a predetermined level set inadvance, in consideration of a danger to the human body. Examples of thelaw or the like relevant to the regulation of the leaked magnetic fieldinclude a guideline set by International Commission on Non-IonizingRadiation Protection (ICNIRP: published in 2010). In addition, in orderto enable mutual connection between all of the power transmissionapparatuses T and the power reception apparatus R described above to beused, as a result, it is necessary for both of the power transmissionapparatus and the power reception apparatus to use a frequency in apredetermined range set in advance, and thus, it is necessary for thefrequency in the predetermined range described above or a frequency bandto follow the recommendation of an international organization such asInternational Organization for Standardization (ISO) or InternationalElectrotechnical Commission (IEC), as the law or the like describedabove. Further, a lower limit value of a transfer efficiency that alsoconsiders a predetermined positional shift between the powertransmission coil TC and the power reception coil RC is also defined bythe international organization described above, and thus, a high powertransfer efficiency is required.

On the other hand, the power reception coil RC of the power receptionapparatus R that receives power from the power transmission coil TC bythe magnetic field resonance method described above outputs the receivedpower to the power reception unit RV. Accordingly, the power receptionunit RV converts output corresponding to the power (for example,high-frequency power of 85 kilohertz), for example, into adirect-current (DC) current by a power conversion unit that is notillustrated, and outputs the DC current to the storage battery of theelectric vehicle. Accordingly, a necessary amount of power is charged inthe storage battery.

In addition, as illustrated in the upper portion of FIG. 2 , in thepower reception coil RC the power reception apparatus R described aboveof the power transfer system S of the embodiment, a heat release plateCBR of the embodiment is stacked above the power reception coil RC (theupper side in FIG. 2 ) by interposing an insulating resin layer (notillustrated in FIG. 2 ) having excellent thermal conductivitytherebetween. The heat release plate CBR is a plate-shaped heat releaseplate for cooling the power reception coil RC itself by diffusing theJoule heat described above that is generated in the power reception coilRC as a result of receiving power from the power transmission coil TCthrough the resin layer described above, and includes a plurality ofheat release members described below. Note that, in FIG. 2 , an externalperspective view of only the outline of the heat release plate CBR ofthe embodiment that is stacked on the power reception coil RC isillustrated by using a broken line.

Further, in the power reception apparatus R, a magnetic plate MR and ashielding plate SR for reducing the leaked magnetic field describedabove from the power reception coil RC are stacked between the lowersurface of the vehicle body of the electric vehicle in which the powerreception apparatus R is mounted and the power reception apparatus Rdescribed above (more specifically, as illustrated in FIG. 2 , betweenthe heat release plate CBR and the lower surface of the vehicle body).At this time, the shielding plate SR may be provided as an exteriorplate or a component in a position where the power reception coil RC isprovided on the lower surface of the vehicle body of the electricvehicle described above. In addition, each of the heat release plateCBR, the magnetic plate MR, and the shielding plate SR may be closelystacked, or may be stacked separated at a distance that is optimized inadvance. In addition, the area of the surface of the magnetic plate MRand the shielding plate SR facing the heat release plate CBR is greaterthan the area of a winding surface of a coil described below that isincluded in the power reception coil RC, and it is preferable that thearea is less than or equal to four times the area of the winding surface(that is, two times in terms of one side of a square exemplified in FIG.2 ).

On the other hand, as illustrated in the lower portion of FIG. 2 , inthe power transmission coil TC of the power transmission apparatus Tdescribed above of the power transfer system S of the embodiment, a heatrelease plate CBT of the embodiment is stacked below the powertransmission coil TC (the lower side in FIG. 2 ) by interposing aninsulating resin layer (not illustrated in FIG. 2 ) having excellentthermal conductivity therebetween. The heat release plate CBT is aplate-shaped heat release plate for cooling the power transmission coilTC itself by diffusing the Joule heat described above that is generatedin the power transmission coil TC as a result of transmitting power tothe power reception coil RC through the resin layer described above, andincludes a plurality of heat release members described below. Note that,in FIG. 2 , as with the heat release plate CBR, an external perspectiveview of only the outline of the heat release plate CBT of the embodimentis illustrated by using a broken line. In addition, the heat releaseplate CBR described above and the heat release plate CBT described abovehave the same configuration, and the details of each of the heat releaseplate CBR and the heat release plate CBT will be described below byusing FIGS. 7A and 7B, as the details of the configuration of the heatrelease plate CBT.

Further, in the power transmission apparatus T, a magnetic plate MT anda shielding plate ST for reducing the leaked magnetic field describedabove from the power transmission coil TC are stacked between the groundsurface in a position where the power transmission apparatus T isprovided and the power transmission apparatus T described above (morespecifically, as illustrated in FIG. 2 , between the heat release plateCBT and the ground surface). At this time, each of the heat releaseplate CBT, the magnetic plate MT, and the shielding plate ST may beclosely stacked, or may be stacked separated at a distance that isoptimized in advance. In addition, the area of the surface of themagnetic plate MT and the shielding plate ST facing the heat releaseplate CBT is greater than the area of a winding surface of a coildescribed later that is included in the power transmission coil TC, andit is preferable that the area is less than or equal to four times thearea of the winding surface (that is, two times in terms of one side ofa square exemplified in FIG. 2 ).

Further, it is preferable that a material of which a relative magneticpermeability, for example, is greater than or equal to 100 is used asthe material of each of the magnetic plate MR and the magnetic plate MTdescribed above. In this case, examples of the material of which therelative magnetic permeability is greater than or equal to 100 includeiron, nickel, cobalt, an alloy including these (for example, anickel-zinc-based soft magnetic material), and the like. Note that, fromthe viewpoint of preventing a breakage, it is preferable that a magneticbody as a material is pulverized, is mixed with a resin or the like, andis fixed to be the magnetic plate MR and the magnetic plate MT such thatthe magnetic plate MR and the magnetic plate MT themselves haveflexibility. Further, from the viewpoint of reducing an inductioncurrent, it is preferable that a material of which theelectroconductivity, for example, is less than or equal to 10³siemens/meters (S/m) is used as the material of the magnetic plate MRand the magnetic plate MT. In addition, it is preferable that thethickness of each of the magnetic plate MR and the magnetic plate MTthemselves, for example, is approximately 0.1 millimeters to 2millimeters. In contrast, it is preferable that a material of which theelectroconductivity, for example, is greater than or equal to 10⁴siemens/meters (S/m) is used as the material of each of the shieldingplate SR and the shielding plate ST described above. In this case,examples of the material of which the electroconductivity is greaterthan or equal to 10⁴ siemens/meters include carbon fiber reinforcedplastic (CFRP), copper, aluminum, iron (for example, stainless steel asan exterior material of the electric vehicle), and the like.

Then, in the configuration described above, the heat release plate CBRand the heat release plate CBT correspond to an example of a “heatrelease means” according to the present invention, the magnetic plate MRand the magnetic plate MT correspond to an example of a “magnetic means”according to the present invention, and the shielding plate SR and theshielding plate ST correspond to an example of a “shielding means”according to the present invention.

(ii) Configuration of Power Transmission Coil TC (Power Reception CoilRC)

Next, the details of the configuration of the power transmission coil TCand the power reception coil RC described above will be described byusing FIG. 3 to FIG. 6 . Note that, the power transmission coil TC andthe power reception coil RC of the embodiment basically have the sameconfiguration. That is, it is preferable that the configuration of thepower transmission loop coil TL described above is basically identicalto the configuration of the power reception loop coil RL describedabove. In addition, it is preferable that the configuration of the powertransmission open coil TO described above is basically identical to theconfiguration of the power reception open coil RO described above.Further, it is preferable that a position relationship between the powertransmission loop coil TL and the power transmission open coil TOdescribed above in the power transmission coil TC is basically identicalto a position relationship between the power reception loop coil RL andthe power reception open coil RO described above in the power receptioncoil RC. Accordingly, in the following description, the structure of thepower transmission coil TC will be described. Note that, the size of thepower transmission coil TC may be larger than that of the powerreception coil RC. In addition, FIG. 3 to FIG. 5 are plan viewsillustrating the structure of the power transmission coil TC of theembodiment, and FIG. 6 is a partial sectional view illustrating thestructure of the power transmission coil TC of the embodiment. At thistime, FIG. 3 to FIG. 5 are plan views when the power transmission coilTC is seen from the power transmission unit TR side (the heat releaseplate CBT side in FIG. 2 ) in the power transmission apparatus T.

As illustrated in the plan view of FIG. 3 , the power transmission coilTC of the embodiment has a configuration in which the power transmissionloop coil TL, and the power transmission open coil TO in which a coilCL1 that is a part thereof is illustrated by a broken line in FIG. 3 arestacked in a paper surface direction of FIG. 3 through an insulatingfilm BF (the details will be described below). Note that, as illustratedin FIG. 3 , the power transmission loop coil TL and the coil CL1described above are formed on the same layer in the power transmissioncoil TC. On the other hand, the power transmission open coil TO has aconfiguration in which the coil CL1 described above that is illustratedby a broken line in FIG. 3 , and a coil CL2 that is not illustrated inFIG. 3 are stacked in the paper surface direction of FIG. 3 through thefilm BF described above. Note that, in the embodiment, the film BF isused in order to insulate between the coil CL1 of the power transmissionopen coil TO and the power transmission loop coil TL, and the coil CL2of the power transmission open coil TO, and an insulating material suchas a glass epoxy material can also be used. In addition, in order toefficiently release the generated heat as the power transmission coilTC, for example, a material for a thin film in which ceramic particlesand the like are dispersed can also be used. Further, the windingcenters of copper thin film wires described below that configure thepower transmission loop coil TL, the coil CL1, and the coil CL2,respectively, are identical or approximately identical to each other.Further, in addition, the surface on which the power transmission loopcoil TL and the coil CL1 are formed, illustrated in FIG. 3 , correspondsto the lower surface of the power transmission coil TC, in FIG. 2 .

Then, as illustrated in FIG. 3 , the power transmission loop coil TLincludes a connection terminal O1 and a connection terminal O2 that areconnected to the power transmission unit TR, on one side of theoutermost circumference portion. In addition, the power transmissionloop coil TL, for example, has a configuration in which the copper thinfilm wire is wound in three rotations (three turns) in the same layer ofthe power transmission coil TC as that of the coil CL1, in which bothend portions (in FIG. 3 , the center of the right side portion) are theconnection terminal O1 and the connection terminal O2 described above.Note that, the copper thin film wire described above that configures thepower transmission loop coil TL has the same width and the samethickness over the entire circumference of the power transmission loopcoil TL. Further, in the power transmission loop coil TL, linearportions are provided in the upper side portion, the lower side portion,the left side portion, and the right side portion in FIG. 3 ,respectively, and the linear portions are connected through curveportions, respectively. Note that, in FIG. 3 , mutual insulation in aposition where the power transmission loop coil TL intersects with thecoil CL1, and mutual insulation in a position where the copper thin filmwires themselves configuring the power transmission loop coil TLintersect with each other, for example, are respectively maintained byforming a jumper wire such that one exceeds the other.

On the other hand, as a relationship in the copper thin film wiresconfiguring the power transmission loop coil TL, the coil CL1, and thecoil CL2 described above, respectively, a width to which the entirewidth of one side in the winding of the power transmission loop coil TLand the entire width of one side in the winding of the coil CL1 areadded (illustrated by a reference numeral “W1” in FIG. 3 ) isapproximately identical to the entire width of corresponding side in thewinding of the coil CL2, as with a first embodiment.

On the other hand, in the coil CL1 configuring the power transmissionopen coil TO that is formed on the same layer of the power transmissioncoil TC as that of the power transmission loop coil TL described above,the outermost circumference portion thereof is an open end T1, asillustrated by the broken line in FIG. 3 . Then, the coil CL1 has aconfiguration in which, for example, the copper thin film wire is woundinto the shape of a spiral in two and a half rotations (2.5 turns), in acounterclockwise direction starting from the open end T1, toward theinnermost circumference portion from the outermost circumferenceportion. In addition, a via V for configuring electric connection withrespect to the coil CL2 that is stacked directly below the coil CL1 inthe paper surface direction of FIG. 3 is connected to the innermostcircumference portion. Note that, the copper thin film wire describedabove that configures the coil CL1 has the same thickness over theentire circumference of the coil CL1. In contrast, as illustrated inFIG. 3 , the width of the copper thin film wire increases toward aportion in the innermost circumference end portion to which the via V isconnected from the open end T1 in the outermost circumference endportion of the coil CL1. Further, in the coil CL1, linear portionsparallel to each other are provided in the upper side portion, the lowerside portion, the left side portion, and the right side portion in FIG.3 , respectively, and the linear portions are connected through curveportions approximately in the shape of a concentric circular arc,respectively. Then, the width of the copper thin film wire configuringthe coil CL1 is constant in each of the linear portions, but increasestoward the innermost circumference end portion in each of the curveportions for connecting the linear portions. At this time, the width ofthe copper thin film wire configuring the coil CL1 may increase towardthe innermost circumference end portion from the outermost circumferenceend portion, as the entire coil CL1, and even in a case where the widthdecreases toward the innermost circumference end portion from theoutermost circumference end portion, for example, temporarily(partially), the effect of the power transfer using the power transfersystem S of the embodiment is not affected. The coil CL1 corresponds toan example of an “out-in winding wire” according to the presentinvention.

Next, the configuration of the coil CL2 configuring the powertransmission open coil TO that is stacked directly below the powertransmission loop coil TL and the coil CL1 described above via the filmBF described above will be described by using FIG. 4 . Note that, FIG. 4is a plan view illustrating only the coil CL2 by taking out the coilCL2.

As illustrated in FIG. 4 , in the coil CL2 configuring the powertransmission open coil TO, along with the coil CL1 described above, thevia V described above for configuring electric connection with respectto the coil CL1 described above is connected to the innermostcircumference portion. That is, the coil CL1 and the coil CL2 areconnected in series over the transmission of the power transmission coilTC. Then, the coil CL2 has a configuration in which, for example, thecopper thin film wire is wound into the shape of a spiral in ten and ahalf rotations (10.5 turns), in a clockwise direction starting from thevia V (that is, a direction opposite to the coil CL1), toward theoutermost circumference portion from the innermost circumferenceportion. In addition, the outermost circumference portion is an open endT2. Note that, as illustrated in FIG. 4 , a position in the coil CL2 towhich the via V is connected is shifted inwardly in a radial directionof the coil CL2 to be aligned with the coil CL1. In addition, the copperthin film wire described above that configures the coil CL2 has the samewidth and the same thickness over the entire circumference of the coilCL2. Further, in the coil CL2, as with the coil CL1, linear portionsparallel to each other are provided in the upper side portion, the lowerside portion, the left side portion, and the right side portion in FIG.3 , and each the linear portions is connected through curve portionsapproximately in the shape of a concentric circular arc, respectively.

Here, as a relationship in copper thin film wires configuring the powertransmission loop coil TL, the coil CL1, and the coil CL2 describedabove, respectively, each of the copper thin film wires is wound suchthat the number of windings of the copper thin film wire of the coil CL1that is wound in the counterclockwise direction described above (two anda half rotations (2.5 turns)) is different from the number of windingsof the copper thin film wire of the coil CL2 that is wound in theclockwise direction described above (ten and a half rotations (10.5turns)), in the same layer as that of the power transmission loop coilTL. In addition, the width of the copper thin film wire of the coil CL2is generally narrower than the width of the copper thin film wire of thecoil CL1 such that the width W1 to which the entire width of one side inthe winding of the power transmission loop coil TL and the entire widthof one side in the winding of the coil CL1 are added (refer to FIG. 3 )is approximately identical to the entire width of one corresponding sidein the winding of the coil CL2 (illustrated by a reference numeral “W2”in FIG. 4 ). Then, the coil CL1 and the coil CL2 are connected in seriesthrough the via V connected to each of the innermost circumferenceportions. Accordingly, the winding to the innermost circumferenceportion from the outermost circumference portion of the coil CL1 isswitched back (folded back) in an opposite direction in the innermostcircumference portion, and thus, the coil CL2 is wound to the outermostcircumference portion from the innermost circumference portion. The coilCL2 corresponds to an example of an “in-out winding wire” according tothe present invention.

Next, a position relationship in the copper thin film wires thatconfigure the power transmission loop coil TL and the power transmissionopen coil TO described above (that is, the coil CL1 and the coil CL2described above), respectively, will be described by using FIG. 5 . Notethat, FIG. 5 is a plan view illustrating a state in which the powertransmission loop coil TL and the coil CL1 overlap with the coil CL2, inwhich the power transmission loop coil TL and the coil CL1 areillustrated by a solid line, and the coil CL2 that is stacked directlybelow the power transmission loop coil TL and the coil CL1 via the filmBF (not illustrated in FIG. 5 ) is illustrated by a broken line,respectively.

As illustrated by the solid line in FIG. 5 , in the coil CL1 that iswound toward the inner circumference from the outer circumference and isconnected to the coil CL2 through the via V in the innermostcircumference portion, each of the curve portions is formed and thecopper thin film wire is wound such that the position of the linearportion is shifted to the inner circumference side by a quarter of thepitch in the winding of the copper thin film wire (that is, a distancebetween the center lines of the adjacent copper thin film wires on eachof the sides, in the radial direction of the winding, and the sameapplies to the followings), for each quarter circle.

On the other hand, as illustrated by the solid line in FIG. 5 , thepower transmission loop coil TL is stacked along each of the sides ofthe coil CL2, and each of the connection terminal O1 and the connectionterminal O2 protrudes to the outside the winding. Further, asillustrated by the broken line in FIG. 5 , even in the coil CL2 that iswound toward the outer circumference from the inner circumference and isconnected to the coil CL1 in series through the via V in the innermostcircumference portion, each of the curve portions is formed and thecopper thin film wire is wound such that the position of the linearportion is shifted to the outer circumference side by a quarter of thepitch in the winding of the copper thin film wire, for each quartercircle. Then, as illustrated in FIG. 5 , the power transmission loopcoil TL in which the coil CL1 described above is wound around the innercircumference side is stacked along each of the sides of the coil CL2.

As illustrated in FIG. 5 , in the power transmission coil TC in whichthe power transmission loop coil TL and the coil CL1, and the coil CL2are stacked, the copper thin film wires configuring the powertransmission loop coil TL and the power transmission open coil TO (thecoil CL1 and the coil CL2), respectively, are stacked to approximatelyoverlap with each other, on each of the up, down, right, and left sides.

Next, a stacked state of the power transmission loop coil TL and thecoil CL1, and the coil CL2 described above, and a connection statebetween the coil CL1 and the coil CL2 will be described by using FIG. 6as a sectional view of an A-A′ part illustrated in FIG. 5 .

As illustrated in FIG. 6 , in the left side portion of FIG. 3 to FIG. 5, the coil CL1 and the coil CL2 are stacked by interposing the film BFtherebetween, and the coil CL1 and the coil CL2 are electricallyconnected to each other through the via V. The winding of the coil CL1in the counterclockwise direction described above is switched back(folded back) in the position of the via V, and thus, the winding of thecoil CL2 in the clockwise direction described above is formed. On theother hand, even though it is not illustrated in FIG. 6 , the powertransmission loop coil TL is stacked in the same layer as that of thecoil CL1, and the coil CL1 and the power transmission loop coil TL areinsulated from each other.

(iii) Configuration of Heat Release Plate CBT (Heat Release Plate CBR)

Next, the details of the configuration of the heat release plate CBT andthe heat release plate CBR of the embodiment described above will bedescribed by using FIGS. 7A and 7B. Note that, the heat release plateCBT and the heat release plate CBR of the embodiment basically have thesame configuration, as described above. Accordingly, in the followingdescription, the structure of the heat release plate CBT that is stackedon the power transmission coil TC through the resin layer describedabove will be described. In addition, FIG. 7A is a plan viewillustrating the structure of the heat release plate of the embodiment,and is a plan view when the heat release plate CBT is seen from thepower transmission unit TR side (in FIG. 2 , the side of the magneticplate MT and the shielding plate ST), in the power transmissionapparatus T. Further, FIG. 7B is a side view when the power transmissioncoil TC of the embodiment that is provided with the heat release plateCBT is seen from a lower direction to an upper direction in FIG. 7A.Note that, in FIG. 7A, the power transmission loop coil TL and the coilCL1 in the power transmission coil TC on which the heat release plateCBT is stacked are illustrated by a broken line.

As illustrated in FIG. 7A, the heat release plate CBT of the embodimentis formed as an aggregation of 24 heat release member CB0 to heatrelease member CB23 divided by gaps GP that are radially formed with thecenter of the power transmission coil TC as a center, and have a widthof approximately 1 millimeter. Each of the heat release member CB0 tothe heat release member CB23, for example, is formed of a metal platethat has excellent thermal conductivity and is in the shape of a flatplate (for example, an aluminum plate having a thickness of 0.1millimeters to 5 millimeters), and all of the heat release members arestacked on the power transmission coil TC in the same plane. Inaddition, as illustrated in FIG. 7A, the shape of the outer edge of theheat release plate CBT including the heat release member CB0 to the heatrelease member CB23 together is approximately similar to the shape ofthe outer edge of the power transmission coil TC. Further, the shape ofthe inner edge of the heat release plate CBT is a shape along the inneredge of the innermost circumference portion of the power transmissioncoil TC including the power transmission loop coil TL and the coil CL1.Then, the length of each of the heat release member CB0 to the heatrelease member CB23 in the radial direction of the power transmissioncoil TC (illustrated by a reference numeral “W3” in FIGS. 7A and 7B) isapproximately twice the width to which the width of the copper thin filmwire configuring the power transmission loop coil TL and the entirewidth of one side in the winding of the coil CL1 are added (refer to thereference numeral “W1” in FIG. 3 ). For this reason, the position of theouter edge of the heat release plate CBT described above is outside theouter edge of the power transmission coil TC when seen from the centerof the power transmission coil TC.

Here, it is considered that the reason that the gap GP in the heatrelease plate CBT is radially formed as described above is because in acase where the entire heat release plate is formed of one metal platewithout having the gap GP (refer to a third comparative exampledescribed below), the generation of an eddy current (an eddy current asan induction current) in the heat release plate due to the transmissionof power from the power transmission coil TC increases, and thus, theheat release plate itself becomes a heat generation source and aradiation source of an electromagnetic wave. For this reason, the heatrelease plate CBT of the embodiment includes a plurality of heat releasemember CB0 to heat release member CB23 with the radial gaps GP (in otherwords, the gaps GP in a direction intersecting with the eddy currentdescribed above), in order to suppress the generation of the eddycurrent.

On the other hand, as illustrated in FIG. 7B, the heat release plate CBTof the embodiment is stacked on the power transmission coil TC byinterposing the insulating resin layer CP described above therebetween.The resin layer CP is a resin layer having flexibility. The heat releaseplate CBT is stacked on the power transmission coil TC by interposingthe resin layer CP therebetween, and thus, a sufficient heat releaseeffect by using the heat release plate CBT formed of a metal plate and aheat release effect by improving adhesiveness between the powertransmission coil TC and the heat release plate CBT (a contact arearatio) are compatible. In addition, the heat release plate CBT isstacked on the power transmission coil TC by interposing the resin layerCP therebetween, and thus, discharge that is caused by directly stackingthe heat release plate CBT on the power transmission coil TC isprevented. Specifically, for example, a so-called thermal conductivesheet formed of a non-silicone-based acrylic sheet can be used as theresin layer CP, and as a desirable specification thereof, it ispreferable to use a material having a thickness of approximately 1millimeter, a thermal conductance rate of approximately 5watts/meter·kelvin (W/m·k), and a volume resistivity of approximately1.0×10¹¹ ohms·centimeter (Ω·cm).

(II) Modification Embodiment

Next, modification embodiments of the present invention will bedescribed by using FIG. 8 to FIG. 12 . Each of the modificationembodiments described below are embodiments in which the shape of theheat release plate CBT of the embodiment is variously modified. At thistime, the structure and the like of each of a power transmission coil(or a power reception coil) on which a heat release plate of each of themodification embodiments is stacked and a resin layer are the same asthose of the power transmission coil TC (or the power reception coil RC)of the embodiment. Accordingly, in FIG. 8 to FIG. 12 , the samereference numerals will be applied to the same configuration members asthose of the power transmission coil TC of the embodiment, and thedetailed description thereof will be omitted. In addition, in FIG. 8 toFIG. 12 , the power transmission loop coil TL and the coil CL1 of thepower transmission coil TC of each of the modification embodiments onwhich the heat release plate of each of the modification embodiments isstacked are illustrated by a broken line.

Further, the heat release plate provided in a power transmissionapparatus of each of the modification embodiments, and the heat releaseplate provided in a power reception apparatus of each of themodification embodiments have the same configuration. Accordingly, inthe following description, the heat release plate provided in the powertransmission apparatus of each of the modification embodiments will bedescribed.

(i) First Modification Embodiment

First, a first modification embodiment will be described by using FIG. 8. Note that, FIG. 8 is a plan view illustrating the structure of a heatrelease plate of the first modification embodiment, and is a plan viewwhen the heat release plate of the first modification embodiment is seenfrom a power transmission unit side of the first modification embodimentin a power transmission apparatus of the first modification embodiment.

As illustrated in the plan view of FIG. 8 , a heat release plate CBT-1of the first modification embodiment is formed as an aggregation of 24heat release member CB100 to heat release member CB123 divided by thegaps GP that are radially formed with the center of the powertransmission coil TC as a center, as with the heat release plate CBT ofthe embodiment. Each of the heat release member CB100 to the heatrelease member CB123, for example, is formed of a metal plate that hasexcellent thermal conductivity and is in the shape of a flat plate (forexample, an aluminum plate having the same thickness as that of the heatrelease member CB0 to the heat release member CB23 of the embodiment),and all of the heat release members are stacked on the powertransmission coil TC in the same plane, by interposing the resin layerCP therebetween. On the other hand, as illustrated in FIG. 8 , the shapeof the outer edge of the heat release plate CBT-1 including the heatrelease member CB100 to the heat release member CB123 together isapproximately similar to the shape of the outer edge of the powertransmission coil TC. Further, the shape of the inner edge of the heatrelease plate CBT-1 is a shape along the inner edge of the innermostcircumference portion of the power transmission coil TC including thepower transmission loop coil TL and the coil CL1. Then, the length ofeach of the heat release member CB100 to the heat release member CB123in the radial direction of the power transmission coil TC is differentfrom that of the heat release plate CBT of the embodiment, and isapproximately 1.1 times the width to which the width of the copper thinfilm wire configuring the power transmission loop coil TL and the entirewidth of one side in the winding of the coil CL1 are added (refer to thereference numeral “W1” in FIG. 3 ). That is, the position of the outeredge of the heat release plate CBT-1 described above is slightly outsidethe position of the outer edge of the power transmission coil TC whenseen from the center of the power transmission coil TC. Note that, thereason that the gap GP in the heat release plate CBT-1 is radiallyformed as described above is the same as that of the heat release plateCBT of the embodiment.

(ii) Second Modification Embodiment

Next, a second modification embodiment will be described by using FIG. 9. Note that, FIG. 9 is a plan view illustrating the structure of a heatrelease plate of the second modification embodiment, and is a plan viewwhen the heat release plate of the second modification embodiment isseen from a power transmission unit side of the second modificationembodiment in a power transmission apparatus of the second modificationembodiment.

As illustrated in the plan view of FIG. 9 , a heat release plate CBT-2of the second modification embodiment is formed as an aggregation of 24heat release member CB150 to heat release member CB173 divided by thegaps GP that are radially formed with the center of the powertransmission coil TC as a center, as with the heat release plate CBT ofthe embodiment. Each of the heat release member CB150 to the heatrelease member CB173, for example, is formed of a metal plate that hasexcellent thermal conductivity and is in the shape of a flat plate (forexample, an aluminum plate having the same thickness as that of the heatrelease member CB0 to the heat release member CB23 of the embodiment),and all of the heat release members are stacked on the powertransmission coil TC in the same plane, by interposing the resin layerCP therebetween. On the other hand, as illustrated in FIG. 9 , the shapeof the outer edge of the heat release plate CBT-2 including the heatrelease member CB150 to the heat release member CB173 together isapproximately similar to the shape of the outer edge of the powertransmission coil TC. Further, the shape of the inner edge of the heatrelease plate CBT-2 is a shape along the inner edge of the innermostcircumference portion of the power transmission coil TC including thepower transmission loop coil TL and the coil CL1. Then, the length ofeach of the heat release member CB150 to the heat release member CB173in the radial direction of the power transmission coil TC (refer to areference numeral “W4” in FIG. 9 ) is different from that of the heatrelease plate CBT of the embodiment, and is approximately three timesthe width to which the width of the copper thin film wire configuringthe power transmission loop coil TL and the entire width of one side inthe winding of the coil CL1 are added (refer to the reference numeral“W1” in FIG. 3 ). For this reason, the position of the outer edge of theheat release plate CBT-1 described above is outside the position of theouter edge of the power transmission coil TC when seen from the centerof the power transmission coil TC. Note that, the reason that the gap GPin the heat release plate CBT-2 is radially formed as described above isthe same as that of the heat release plate CBT of the embodiment.

(iii) Third Modification Embodiment

Next, a third modification embodiment will be described by using FIG. 10. Note that, FIG. 10 is a plan view illustrating the structure of a heatrelease plate of the third modification embodiment, and is a plan viewwhen the heat release plate of the third modification embodiment is seenfrom a power transmission unit side of the third modification embodimentin a power transmission apparatus of the third modification embodiment.

As illustrated in the plan view of FIG. 10 , a heat release plate CBT-3of the third modification embodiment has approximately the same size asthat of the heat release plate CBT of the embodiment, and is formed asan aggregation of four square heat release member CB30 to heat releasemember CB33 divided by linear gaps GP that are formed into the shape ofa cross with the center of the power transmission coil TC as a center.At this time, the shapes of the heat release member CB30 to the heatrelease member CB33 are approximately identical to each other except foran inner edge portion corresponding to the innermost circumference ofthe power transmission coil TC. In addition, each of the heat releasemember CB30 to the heat release member CB33, for example, is formed of ametal plate that has excellent thermal conductivity and is in the shapeof a flat plate (for example, an aluminum plate having the samethickness as that of the heat release member CB0 to the heat releasemember CB23 of the embodiment), and all of the heat release members arestacked on the power transmission coil TC in the same plane, byinterposing the resin layer CP therebetween. On the other hand, asillustrated in FIG. 10 , the shape of the outer edge of the heat releaseplate CBT-3 including the heat release member CB30 to the heat releasemember CB33 together is approximately shape similar to the shape of theouter edge of the power transmission coil TC. Then, the length of theside forming the gap GP in each of the heat release member CB30 to theheat release member CB33 is longer than the length of one side of thepower transmission coil TC. For this reason, the position of the outeredge of the heat release plate CBT-3 described above is outside theposition of the outer edge of the power transmission coil TC when seenfrom the center of the power transmission coil TC. Note that, the reasonthat the gap GP in the heat release plate CBT-3 is disposed into theshape of a cross illustrated in FIG. 10 (a radial shape) is because aneddy current in the heat release plate CBT-3 is divided by the gaps GP,and thus, the generation of the eddy current is suppressed, as with theheat release plate CBT of the embodiment.

(iv) Fourth Modification Embodiment

Next, a fourth modification embodiment will be described by using FIG.11 . Note that, FIG. 11 is a plan view illustrating the structure of aheat release plate of the fourth modification embodiment, and is a planview when the heat release plate of the fourth modification embodimentis seen from a power transmission unit side of the fourth modificationembodiment in a power transmission apparatus of the fourth modificationembodiment.

As illustrated in the plan view of FIG. 11 , a heat release plate CBT-4of the fourth modification embodiment has a shape in which a set of gapsGP in facing positions (in a case exemplified in FIG. 11 , a set offacing gaps GP in a horizontal direction of FIG. 11 ) are eliminatedfrom the heat release plate CBT-3 of the third modification embodiment.That is, as illustrated in FIG. 11 , the heat release plate CBT-4 of thefourth modification embodiment is formed as an aggregation of two squareheat release member CB35 and heat release member CB36 divided by lineargaps GP that are disposed in the facing positions when seen from thecenter of the power transmission coil TC. At this time, the shapes ofthe heat release member CB35 and the heat release member CB36 areapproximately identical to each other except for the inner edge portioncorresponding to the innermost circumference of the power transmissioncoil TC. In addition, each of the heat release member CB35 and the heatrelease member CB36, for example, is formed of a metal plate that hasexcellent thermal conductivity and is in the shape of a flat plate (forexample, an aluminum plate having the same thickness as that of the heatrelease member CB0 to the heat release member CB23 of the embodiment),and both of the heat release members are stacked on the powertransmission coil TC in the same plane, by interposing the resin layerCP therebetween. On the other hand, as illustrated in FIG. 11 , theshape of the outer edge of the heat release plate CBT-4 including theheat release member CB35 and the heat release member CB36 together isapproximately similar to the shape of the outer edge of the powertransmission coil TC. Then, the length of the side forming the gap GP ineach of the heat release member CB35 and the heat release member CB36 islonger than the length of one side of the power transmission coil TC.For this reason, the position of the outer edge of the heat releaseplate CBT-4 described above is outside the position of the outer edge ofthe power transmission coil TC when seen from the center of the powertransmission coil TC. Note that, the reason that the gap GP in the heatrelease plate CBT-4 is disposed in the position of the radial shapeillustrated in FIG. 10 is because an eddy current in the heat releaseplate CBT-4 is divided by the gaps GP, and thus, the generation of theeddy current is suppressed, as with the heat release plate CBT of theembodiment.

(v) Fifth Modification Embodiment

Finally, a fifth modification embodiment will be described by using FIG.12 . Note that, FIG. 12 is a plan view illustrating the structure of aheat release plate of the fifth modification embodiment, and is a planview when the heat release plate of the fifth modification embodiment isseen from a power transmission unit side of the fifth modificationembodiment in a power transmission apparatus of the fifth modificationembodiment.

As illustrated in the plan view of FIG. 12 , in a heat release plateCBT-5 of the fifth modification embodiment, only one gap GP is provided,compared to the heat release plate CBT-3 of the third modificationembodiment and the heat release plate CBT-4 of the fourth modificationembodiment. That is, as illustrated in FIG. 12 , the heat release plateCBT-5 of the fifth modification embodiment is formed as one heat releaseplate divided by only one linear gap GP. Then, the heat release plateCBT-5, for example, is formed of a metal plate that has excellentthermal conductivity and is in the shape of a flat plate (for example,an aluminum plate having the same thickness as that of the heat releasemember CB0 to the heat release member CB23 of the embodiment), and isstacked on the power transmission coil TC by interposing the resin layerCP therebetween. On the other hand, as illustrated in FIG. 12 , theshape of the outer edge of the heat release plate CBT-5 is approximatelysimilar to the shape of the outer edge of the power transmission coilTC. Then, the length of the side forming the gap GP in the heat releaseplate CBT-5 is longer than the length of one side of the powertransmission coil TC. For this reason, the position of the outer edge ofthe heat release plate CBT-5 described above is outside the position ofthe outer edge of the power transmission coil TC when seen from thecenter of the power transmission coil TC. Note that, the reason that thegap GP is disposed in the heat release plate CBT-5 is because an eddycurrent in the heat release plate CBT-5 is divided by the gap GP, andthus, the generation of the eddy current is suppressed, as with the heatrelease plate CBT of the embodiment.

Note that, as with the third modification embodiment to the fifthmodification embodiment, for example, an effect of facilitatingalignment with respect to the power transmission coil TC in themanufacturing while suppressing the generation of an overcurrent can beobtained by decreasing the number of gaps GP. On the other hand, in acase where the number of gaps GP is large, the size per one heat releasemember can be decreased, which can be advantageous from the viewpoint ofmanufacturing the heat release member itself.

EXAMPLES

Next, an effect relevant to a reduction in a leaked magnetic field in acase where a power transfer is performed by using the power transfersystem S of the embodiment including the power transmission coil TC andthe power reception coil RC of the embodiment described above will bedescribed as a first example by using FIG. 13 , on the basis of asimulation result of the present inventors. In addition, an effect orthe like relevant to a transfer efficiency in a case where a powertransfer is performed by using the power transfer system S or the likeof the embodiment and each of the modification embodiments including thepower transmission coil TC or the like and the power reception coil RCor the like of the embodiment and each of the modification embodimentsdescribed above will be described as a second example by using thefollowing table and FIG. 14 , on the basis of the simulation resultdescribed above. Further, a heat release effect in the case of using theheat release plate CBT and the heat release plate CBR of the embodimentwill be described as a third example.

(I) First Example

First, the effect relevant to a reduction in the leaked magnetic fielddescribed above will be described by using FIG. 13 . Note that, FIG. 13is a figure illustrating the state of the leaked magnetic field due tothe structure of the power transfer system S of the embodiment. Inaddition, in FIG. 13 , a solid straight line in a horizontal directionof FIG. 13 illustrates the power transmission coil TC and the powerreception coil RC of the embodiment, and including the shielding plateST and the magnetic plate MT, the shielding plate SR and the magneticplate MR, and the heat release plate CBT and the heat release plate CBRcorresponding to the power transmission coil TC and the power receptioncoil RC, respectively, along with the power transmission coil TC and thepower reception coil RC, is illustrated by “(RC, CBR, MR, SR)” and “(TC,CBT, MT, ST)”. In addition, in FIG. 13 , a curve that is broadenedaround the power transmission coil TC and the power reception coil RCillustrates the state of the leaked magnetic field for each intensity,and the intensity is illustrated by a number (the unit is amperes/meter(A/m)) in FIG. 13 . Further, in the power transfer system S in which asimulation result illustrated in FIG. 13 is obtained, a magnetic platehaving a relative magnetic permeability of 1200 and a thickness of 0.1millimeters is used as the magnetic plate MT and the magnetic plate MRdescribed above, and one aluminum plate without having the gap GP havinga thickness of 1 millimeter is used as the shielding plate ST and theshielding plate SR described above. Further, a limit value of the leakedmagnetic field described in the guideline set by ICNIRP (published in2010) as the law or the like described above is 21 amperes/meter.

As found from FIG. 13 , in the case of using the power transfer system Sof the embodiment, the leaked magnetic field that is generated due to apower transfer of the power transmission coil TC and the power receptioncoil RC is shielded by the shielding plate ST and the shielding plateSR, and the magnetic plate MT and the magnetic plate MR. Accordingly, itis considered that the safety of a passenger of the electric vehicle onwhich the power reception coil RC is mounted (the passenger ispositioned on the upper side of FIG. 14 or is positioned outside a rangeillustrated on the upper side) from the leaked magnetic field of greaterthan or equal to the limit value described above is ensured.

(II) Second Example

Next, an effect or the like relevant to a transfer efficiency in a casewhere a power transfer is performed by using the power transfer system Sor the like of the embodiment and each of the modification embodimentsdescribed above will be described by using FIG. 14 , FIGS. 15A-E, andthe following table, on the basis of the simulation result describedabove.

Note that, FIG. 14 is a plan view illustrating the structure of a heatrelease plate of a first comparative example described below, and is aplan view when the heat release plate of the first comparative exampleis viewed from a power transmission unit side of the first comparativeexample in a power transmission apparatus of the first comparativeexample. Further, in FIG. 14 , a power transmission loop coil or thelike of a power transmission coil of the first comparative example onwhich the heat release plate of the first comparative example is stackedis illustrated by a broken line. At this time, the configuration of thepower transmission coil and a resin layer of the first comparativeexample is identical to the configuration of the power transmission coilTC and the resin layer CP of the embodiment, and thus, in FIG. 14 , thesame reference numerals will be applied to the same configurationmembers as those of the power transmission coil TC of the embodiment,and the detailed description thereof will be omitted. In addition, thefollowing table is a table showing a resonance frequency, the value ofan S parameter S11 representing a reflection rate, the value of an Sparameter S21 representing a transfer efficiency, and the value of thetransfer efficiency based on the S parameter S11 and the S parameter S21in the case of using each of the heat release plates of the embodimentand each of the modification embodiments described above, along witheach of the values in the case of using heat release plates of each ofthe comparative examples described below, for example. Further, each ofthe drawings in FIGS. 15A-E is a plan view illustrating a generationstatus of an eddy current or the like in the heat release plate CBT orthe like of the embodiment, each of the modification embodiments, andthe like, with respect to the heat release plate CBT or the like that isstacked on the power transmission coil TC, and the description of thepower transmission coil TC itself other than the heat release plate willbe omitted.

TABLE 1 Resonance S S Transfer Shape and others of frequency parameterparameter efficiency heat release plate (MHz) (S11, dB) (S21, dB) (%)Embodiment 3.4 −27.8 −0.7 85.4 First modification −18.0 −0.9 83.3embodiment Second modification 2.65 −29.88 −0.839 82.5 embodiment Thirdmodification 2.65 −28.673 −0.537 88.5 embodiment Fourth modification2.70 −24.469 −0.591 87.6 embodiment Fifth modification 2.60 −28.609−0.569 87.8 embodiment First comparative 2.7 −27.529 −1.391 72.7 exampleSecond comparative 3.4 −15.6 −1.1 80.0 example Third comparative 7.0−7.8 −17.3 2.3 example

First, the heat release plate of the first comparative example will bedescribed by using FIG. 14 . As illustrated in each of the plan views ofFIG. 14 , a heat release plate CBT-6 of the first comparative example isformed as an aggregation of 24 heat release member CB210 to heat releasemember CB233 divided by the gaps GP that are radially formed with thecenter of the power transmission coil TC as a center, as with the heatrelease plate CBT of the embodiment. Each of the heat release memberCB210 to the heat release member CB233, for example, is formed of ametal plate that has excellent thermal conductivity and is in the shapeof a flat plate (for example, an aluminum plate having the samethickness as that of the heat release member CB0 to the heat releasemember CB23 of the embodiment), and all of the heat release members arestacked on the power transmission coil TC in the same plane, byinterposing the resin layer CP therebetween. On the other hand, asillustrated in FIG. 14 , the shape of the outer edge of the heat releaseplate CBT-6 including the heat release member CB210 to the heat releasemember CB233 together is approximately similar to the shape of the outeredge of the power transmission coil TC. Further, the shape of the inneredge of the heat release plate CBT-6 is different from that of the heatrelease plate CBT of the embodiment, and each of the heat release plateCB210 to the heat release plate CB233 is formed to extend to thevicinity of the center of the heat release plate CBT-6. Accordingly, thelength of each of the heat release member CB210 to the heat releasemember CB233 in the radial direction of the power transmission coil TCis different from that of the heat release plate CBT of the embodiment,and is approximately three times the width to which the width of thecopper thin film wire configuring the power transmission loop coil TLand the entire width of one side in the winding of the coil CL1 areadded (refer to the reference numeral “W1” in FIG. 3 ), and the positionof the outer edge of the heat release plate CBT-6 described above isoutside the position of the outer edge of the of the power transmissioncoil TC when seen from the center of the power transmission coil TC.Note that, the reason that the gap GP in the heat release plate CBT-6 isradially formed as described above is the same as that of the heatrelease plate CBT of the embodiment.

Next, as a second comparative example of the table described above, asimulation result using a power transmission apparatus and a powerreception apparatus in which the power transmission coil TC and thepower reception coil RC of the embodiment, the shielding plate ST andthe shielding plate SR of the embodiment, and the magnetic plate MT andthe magnetic plate RT of the embodiment are provided, but the heatrelease plate CBT and the heat release plate CBR, and the resin layer CPof the embodiment are not provided is illustrated.

Further, as a third comparative example of the table described above, asimulation result using a power transmission apparatus and a powerreception apparatus in which one aluminum plate having the samethickness of 1 millimeter is provided as a heat release plate instead ofthe heat release plate CBT and the heat release plate CBR of theembodiment is illustrated.

Then, as found from the table described above, in the case of using theheat release plate CBT or the like of the embodiment and each of themodification embodiments, and the first comparative example and thesecond comparative example, the resonance frequency is suppressed to alow level as expected, and the transfer efficiency has an excellentvalue of greater than or equal to that of the second comparative examplein which the heat release plate CBT described above or the like is notused. At this time, the transfer efficiency is most excellent in thecase of using the heat release plate CBT or the like of the embodimentand each of the modification embodiments in which the heat releasemember CB0 and the like are divided by the gaps GP having a radial shapeand the heat release member is not provided in each central portionthereof. In contrast, in the third comparative example using the heatrelease plate without having the gap GP, the resonance frequency isextremely transitioned (increases), and the transfer efficiency alsoconsiderably decreases. It is considered that this is because there isno gap GP, and thus, the transfer efficiency decreases due to theinterference of the electromagnetic wave that is caused by the fact thatthe heat release plate itself becomes the radiation source of theelectromagnetic wave due to the eddy current described above generatedin the heat release plate. Here, regarding a change in the transferefficiency described above, the result of a simulation with respect tothe generation status of the eddy current described above that isperformed by the present inventors is illustrated in FIGS. 15A-E. Notethat, in each of FIG. 15A to FIG. 15E, the state of the eddy current(the induction current) that is generated in the heat release plate CBTor the like by a current flowing through the power transmission coil TCis illustrated by large and small arrows.

First, in each of the heat release plate CBT of the embodimentillustrated in FIG. 15A, the heat release plate CBT-3 of the thirdmodification embodiment illustrated in FIG. 15B, and the heat releaseplate CBT-5 of the fifth modification embodiment illustrated in FIG.15C, each looped eddy current as illustrated by minute arrows isgenerated along the shape of the power transmission coil TC (a loopshape) on which the heat release plate is stacked. In contrast, in eachof the heat release members CB0 and the like configuring each of theheat release plate CBT and the like, as illustrated in FIG. 15A to FIG.15C, an eddy current illustrated by large arrows is divided into twogroups toward the inner circumference direction and the outercircumference direction, and further flows along the edge of the heatrelease member CB0 and the like such that the spiral direction isdifferent. The directions of the magnetic fields generated from the eddycurrent (the induction current) generated as described above areopposite to each other, and thus, the magnetic fields cancel each otherout, which, as a result, does not affect a transfer efficiency as thepower transmission coil TC. In contrast, in the case of a heat releaseplate CBT-X3 without having the gap GP that is illustrated in FIG. 15Eas the heat release plate CBT-X3 of the third comparative example, thelooped eddy current flows through the heat release plate CBT-X3 in onedirection (in FIG. 15E, a counterclockwise direction, including the edgeportion), and thus, the directions of all of the magnetic fieldsgenerated from such an eddy current are the same, which, as a result,affects the transfer efficiency of the power transmission coil TC. Onthe other hand, even in the case of the heat release plate CBT-6 of thefirst comparative example illustrated in FIG. 15D, the eddy currentsflowing in opposite directions are generated, as with the heat releaseplate CBT or the like of the embodiment. However, in the case of theheat release plate CBT-6 of the first comparative example, the amount ofeddy current flowing to a portion protruding to the center portion ofthe power transmission coil TC is greater than that of the eddy currentflowing to the outer circumference portion of the heat release plateCBT-6 (that is, the eddy current is biased to the center portion of thepower transmission coil TC), which affects the transfer efficiency asthe power transmission coil TC, as with the case of the heat releaseplate CBT-X3 that is not divided.

Note that, the simulation result shown in the table described above isapplied to the power reception coil RC, and it is not necessary that thepower transmission coil TC provided on the ground surface is providedwith the shielding layer ST or the heat release plate CBT havingconductivity, and there is no person or the like nearby who is affectedby the leaked magnetic field, and thus, it can be said that the magneticplate MT and the shielding plate ST, and the heat release plate CBT arenot required for the power transmission coil TC. However, as found fromthe contents of the table described above, the magnetic plate MT and themagnetic plate MR, and the heat release plate CBT are provided andeffectively function, and thus, it is found that there is an effect oflowering the resonance frequency and of improving the transferefficiency while effectively cooling the power transmission coil TC andthe power reception coil RC. Then, in particular, according to theeffect of lowering the frequency described above, in a case where theresonance frequency as the power transmission coil TC or the powerreception coil RC is adjusted, the length of the copper thin film wireitself of each of the coil CL1 and the like can be decreased, power lossor heat generation due to electric resistance of the copper thin filmwire can be further suppressed. For this reason, as with the powerreception coil RC, it is desirable that the power transmission coil TCis also provided with the shielding plate ST and the magnetic plate MT,and the heat release plate CBT.

(III) Third Example

Finally, an example of the heat release effect of the heat release plateCBT (or the heat release plate CBR) and the resin layer CP of theembodiment described above will be described by the comparison with thecase of not using the heat release plate CBT (or the heat release plateCBR) and/or the resin layer CP.

Note that, the heat release effect as the third example was checked byusing the thermal conductive sheet formed of the non-silicone-basedacrylic sheet described above, and as a specification thereof, by usingthe resin layer CP having a thickness of approximately 1 millimeter, athermal conductance rate of approximately 5 watts/meter·kelvin, and avolume resistivity of approximately 1.0×10¹¹ ohms·centimeter, as theresin layer CP of the third example, and by using square aluminum havinga thickness of 1 millimeter and a size in which one side is 350millimeters (a thermal conductance rate of 236 watts/meter·kelvin), asthe heat release plate CBT (or the heat release plate CBR) of the thirdexample. Note that, at this time, the specification of the powertransmission open coil TC (or the power reception coil RC) of the thirdexample is as follows.

-   -   Size and Others: a square having one side of 300 millimeters, in        which the width of a copper thin film wire portion on each side        of the coil (refer to the reference numeral “W1” in FIG. 3 ) is        75 millimeters    -   Number of Windings of Power Transmission Loop Coil TL: five        rotations (five turns)    -   Number of Windings of Coil CL1: two and a half rotations (2.5        turns)    -   Winding of Coil CL2: 11 and a half rotations (11.5 turns)

Then, in a case where a current of 20 amperes was applied to the powertransmission loop coil TL, the highest temperature of the powertransmission coil TC (or the power reception coil RC) reached 70 degreesin the case of including only the power transmission coil TC (or thepower reception coil RC) without including the heat release plate CBTand the resin layer CP, and the highest temperature of the powertransmission coil TC (or the power reception coil RC) reached 60 degreesin the case of using only the resin layer CP without using the heatrelease plate CBT. In contrast, in a case where the heat release plateCBT was stacked by interposing the resin layer CP therebetween, andthen, a current of 20 amperes flowed through the power transmission loopcoil TL, the highest temperature of the power transmission coil TC (orthe power reception coil RC) only reached 35 degrees. Accordingly, it isfound that a sufficient cooling effect of the power transmission coil TC(or the power reception coil RC) can be obtained by the heat releaseplate CBT and the resin layer CP of the embodiment.

As described above, according to the power transfer using the powertransfer system S of the embodiment including the power transmissioncoil TC and the power reception coil RC of the embodiment (hereinafter,the power transmission coil TC and the power reception coil RC will becollectively referred to as the “power transmission coil TC or thelike”), the heat release plate CBT or the like includes the heat releasemember CB0 and the like that are divided by one or a plurality of gapsGP along the radial direction of the winding surface of the copper thinfilm wire configuring the power transmission coil TC or the like, andthus, the current due to the electromagnetic wave that is generated fromthe power transmission coil TC or the like by the power transfer isdivided, and therefore, a transfer efficiency as the power transfersystem S or the like can also be improved while effectively cooling thepower transmission coil TC or the like from heat that is generated bythe flow of the current.

In addition, the thermally conductive resin layer CP is interposedbetween the power transmission coil TC or the like and the heat releaseplate CBT (and the heat release plate CBR), and thus, the adhesivenessbetween the power transmission coil TC or the like and the heat releaseplate CBT (and the heat release plate CBR) can be increased, and thepower transmission coil TC or the like can be efficiently cooled whileavoiding the risk of discharge from the power transmission coil TC orthe like.

Further, the power transmission coil TC or the like includes the coilCL1 or the like in which the copper thin film wire is wound a pluralityof times, the gap GP of the heat release plate CBT or the like is aplurality of linear gaps GP that are radially formed along the radialdirection of the winding surface, in the plane of the heat release plateCBT or the like parallel to the winding surface of the copper thin filmwire configuring the coil CL1 or the like, and a plurality of heatrelease member CB0 and the like are divided by each of the gaps GP inthe heat release plate CBT or the like, and thus, the power transmissioncoil TC or the like can be efficiently cooled.

Further, in the case of the embodiment and each of the modificationembodiments, each of the heat release member CB0 and the like are formedin a range facing the region of the coil CL1 or the like excluding theinside region from the position of the copper thin film wire woundaround the innermost circumference of the power transmission coil TC orthe like, and thus, the power transmission coil TC can be effectivelycooled by suppressing the generation of the current in the heat releaseplate CBT or the like due to the electromagnetic wave that is generatedin the inside region.

In addition, each of the heat release member CB0 and the like is formedin a range facing the coil CL1 or the like in which the copper thin filmwire is wound and a range facing the outside region from the position ofthe copper thin film wire wound around the outermost circumference ofthe power transmission coil TC or the like, and thus, the powertransmission coil TC or the like can be efficiently cooled by increasingthe size as the heat release plate CBT or the like.

Further, the shielding plate SR disposed between the power transmissioncoil TC or the like and the heat release plate CBT or the like, and aprotection target such as a passenger, and the magnetic plate MRdisposed between the power transmission coil TC or the like and the heatrelease plate CBT or the like, and the shielding plate SR are furtherprovided, and the area of the shielding plate SR and the magnetic plateMR in the plane perpendicular to a straight line toward the protectiontarget from the position of the power transmission coil TC or the likeis greater than the area of the power transmission coil TC or the likein the plane, and thus, the transfer efficiency as the power transfersystem S or the like can be improved while effectively cooling the powertransmission coil TC or the like, and further the protection target canbe effectively protected from the electromagnetic wave that is generatedfrom the power transmission coil TC or the like.

In addition, the power transmission coil TC or the like includes thecoil CL1 or the like, the area of the surface perpendicular to aperpendicular line of the shielding plate SR and the magnetic plate MRthat are in the shape of a plate, in which the perpendicular line iserected in a direction toward the protection target with the center ofthe coil CL1 or the like as a foot, is greater than the area of thewinding surface of the copper thin film wire in the coil CL1 or thelike, and thus, the transfer efficiency as the power transfer system Sor the like can be improved while cooling the power transmission coil TCor the like, and the protection target can be effectively protected fromthe electromagnetic wave that is generated by the power transfer.

Further, the power transmission coil TC or the like includes the powertransmission loop coil TL (or the power reception loop coil RL) and thepower transmission open coil TO (or the power reception open coil RO),and thus, the transfer efficiency can be improved while cooling thepower transmission coil TC or the like, and the protection target can beeffectively protected from the electromagnetic wave.

Further, the power transmission open coil TO (or the power receptionopen coil RO) has serial connection in which the coil CL1 and the coilCL2 are connected in the innermost circumference portion, and in thepower transmission open coil TO (or the power reception open coil RO),the coil CL1 overlaps with the coil CL2 by interposing the film BFtherebetween such that the winding center of the coil CL1 and thewinding center of the coil CL2 are coincident with each other, and thus,the transfer efficiency can be improved while cooling the powertransmission coil TC or the like and reducing the resonance frequency,and the protection target can be effectively protected from theelectromagnetic wave.

In addition, in the power transmission loop coil TL (or the powerreception loop coil RL), the copper thin film wire is concentricallywound with respect to the power transmission open coil TO (or the powerreception open coil RO) a plurality of times, and thus, the transferefficiency of the power can be further improved.

(IV) Other Embodiments

Next, other embodiments of the present invention will be described.

The configuration of the power transfer system S or the like of theembodiment and each of the modification embodiments described above maybe modified as described in (A) to (J) described below. The presentinventors have checked that the same effect as that of the powertransfer system S or the like described above can be obtained even inthe case of adding each of the modifications described below.

(A) The heat release plate CBT or the like of the embodiment and each ofthe modification embodiments, for example, may be thermally connected tothe other heat release member such as a metal plate CBB (for example,may be a metal body of a vehicle or the like in a case where a heatrelease plate CBR is stacked on the power reception coil RC) through athermal connection member TM, on each outer edge, as illustrated in asectional conceptual figure of FIG. 16 . At this time, it is necessarythat the metal plate CBB and the heat release plate CBT or the like areelectrically insulated from each other. In such a configuration, thesize as the heat release member of the heat release plate CBT or thelike substantially increases, and thus, the cooling effect thereof isfurther improved. At this time, the other heat release membercorresponds to an example of a “second heat release means” of thepresent invention. Note that, the metallic shielding plate ST (or theshielding plate SR) may function as the other heat release memberdescribed above.

(B) In the power transmission loop coil TL or the power reception loopcoil RL of the embodiment and each of the modification embodiments, thenumber of windings of each of the power transmission loop coil TL andthe power reception loop coil RL is three rotations (three turns), butthe number of windings may be greater than or equal to two rotations(two turns) or four rotations (four turns), or may be only one rotation(one turn).

(C) In the power transmission open coil TO (or the power reception opencoil RO) of the embodiment and each of the modification embodiments, thenumber of windings of each of the coil CL1 and the coil CL2 thatconfigure the power transmission open coil TO and the power receptionopen coil RO, respectively, is two and a half rotations (2.5 turns) andten and a half rotations (10.5 turns), but the number of windings may bea different value, or the number of winding of the coil CL1 may beidentical to the number of windings of the coil CL2.

(D) In the power transmission open coil TO (or the power reception opencoil RO) of the embodiment and each of the modification embodiments, thepower transmission loop coil TL (or the power reception loop coil RL)and the coil CL1 are formed in the same layer, but the powertransmission loop coil TL (or the power reception loop coil RL) and thecoil CL1 may be formed in different layers, and may be concentricallystacked.

(E) The coil CL1 and the coil CL2 of the embodiment and each of themodification embodiments are connected through the via V in each of theinnermost circumference portions, but the coil CL1 and the coil CL2 maybe insulated from each other.

(F) The order of the coil CL1 and the coil CL2 of the embodiment andeach of the modification embodiments when seen from the side of thepower transmission loop coil TL (or the power reception loop coil RL)may be switched.

(G) The position of the power transmission loop coil TL and the positionof the power transmission open coil TO in the power transmission coil TCof the embodiment may be switched, and the position of the powerreception loop coil RL and the position of the power reception open coilRO in the power reception coil RC of the embodiment may be switched. Inthis case, as the entire power transfer system, the power transmissionloop coil TL of the power transmission coil and the power reception loopcoil RL of the power reception coil may be disposed to face each other.

(H) In the coil CL1 of the embodiment and each of the modificationembodiments, the width increases toward the inner circumference from theouter circumference, but the width of the coil CL1 may be the same overthe entire circumference.

(I) In the embodiment and each of the modification embodiments,capacitors may be further connected to the end portion of the powertransmission open coil TO or the power reception open coil TO that isthe open end in series or in parallel or to the power transmission loopcoil TL or the power reception loop coil RL in parallel, respectively,and parasitic capacity as the power transmission loop coil TO or thepower reception loop coil RO, or the power transmission open coil TL orthe power reception open coil RL may be adjusted, and thus, theresonance frequency may decrease. At this time, in the case ofconnecting the capacitor to any one of the open ends of the powertransmission open coil TO or the power reception open coil RO in series,the terminal of the capacitor that is not connected to any one of theopen ends may be the open end.

(J) In the embodiment and each of the modification embodiments, the gapGP is in the shape of a straight line with a constant width, but the gapGP, for example, may be in the shape of a curve, and the width thereofmay not be constant (for example, a gap in which the inner width isnarrow, and the outer width is wide).

INDUSTRIAL APPLICABILITY

As described above, the present invention can be used in the field of anon-contact power transfer, and in particular, in a case where thepresent invention is applied to the field of a power transfer forcharging a storage battery mounted on an electric vehicle, aparticularly remarkable effect can be obtained.

EXPLANATION OF REFERENCE NUMERALS

-   S POWER TRANSFER SYSTEM-   T POWER TRANSMISSION APPARATUS-   R POWER RECEPTION APPARATUS-   V VIA-   BF FILM-   TR POWER TRANSMISSION UNIT-   RV POWER RECEPTION UNIT-   TC POWER TRANSMISSION COIL-   RC POWER RECEPTION COIL-   MR, MT MAGNETIC PLATE-   SR, ST SHIELDING PLATE-   CP RESIN LAYER-   CBR, CBT, CBT-1, CBT-2, CBT-3, CBT-4, CBT-5, CBT-6, CBT-X3 HEAT    RELEASE PLATE-   TL POWER TRANSMISSION LOOP COIL-   TO POWER TRANSMISSION OPEN COIL-   RL POWER RECEPTION LOOP COIL-   RO POWER RECEPTION OPEN COIL-   O1, O2 CONNECTION TERMINAL-   T1, T2 OPEN END-   CL1, CL2 COIL-   CB0, CB1, CB2, CB3, CB4, CB5, CB6, CB7, CB8, CB9, CB10, CB11, CB12,    CB13, CB14, CB15, CB16, CB17, CB18, CB19, CB20, CB21, CB22, CB23,    CB30, CB31, CB32, CB33, CB35, CB36, CB100, CB101, CB102, CB103,    CB104, CB105, CB106, CB107, CB108, CB109, CB110, CB111, CB112,    CB113, CB114, CB115, CB116, CB117, CB118, CB119, CB120, CB121,    CB122, CB123, CB150, CB151, CB152, CB153, CB154, CB155, CB156,    CB157, CB158, CB159, CB160, CB161, CB162, CB163, CB164, CB165,    CB166, CB167, CB168, CB169, CB170, CB171, CB172, CB173, CB210,    CB211, CB212, CB213, CB214, CB215, CB216, CB217, CB218, CB219,    CB220, CB221, CB222, CB223, CB224, CB225, CB226, CB227, CB228,    CB229, CB230, CB231, CB232, CB233 HEAT RELEASE MEMBER-   GP GAP-   CBB METAL PLATE-   TM THERMAL CONNECTION MEMBER

1. A power transfer apparatus, comprising: a transfer configured toperform a non-contact type power transfer, the transfer including a coilin which a winding wire is wound a plurality of times; a metallic heatrelease configured to cool the transfer, the metallic heat releasefacing a region of the coil excluding a region inside from an innermostperimeter of the winding wire and facing a region outside from anoutermost perimeter of the winding wire, in a plane parallel to awinding surface of the winding wire, and includes heat release membersdivided by one or a plurality of gaps along a radial direction of thewinding surface; and a second heat release that is thermally connectedto, and electrically insulated from, any one of the heat releasemembers, on an outer edge of the metallic heat release, the second heatrelease being a metal part of an object which is equipped with the powertransfer apparatus and receives the power transmission.
 2. The powertransfer apparatus according to claim 1, further comprising: a thermallyconductive resin layer between the transfer and the metallic heatrelease.
 3. The power transfer apparatus according to claim 1, furthercomprising: a shield that is disposed on a side opposite to a powertransmission side of the transfer at a time of power transmission or aside opposite to a power reception side of the transfer at a time ofpower reception when seen from a position of the transfer and themetallic heat release, and is configured to shield an electromagneticwave generated by the power transfer; and a magnetic body that isdisposed between the transfer and the metallic heat release, and theshield, wherein an area of the shield and the magnetic body in a planeperpendicular to a straight line toward the shield and the magnetic bodyfrom the position of the transfer is greater than or equal to an area ofthe transfer in the plane.
 4. The power transfer apparatus according toclaim 3, wherein the straight line is a perpendicular line that iserected in a direction toward the shield and the magnetic body with acenter of the coil as a foot, and an area of a surface perpendicular tothe perpendicular line of the shield and the magnetic body that arerespectively in the shape of a plate is greater than or equal to an areaof the winding surface of the winding wire in the coil.
 5. The powertransfer apparatus according to claim 4, wherein the transfer includes afirst coil that performs the power transmission or the power reception,as the power transfer, and a second coil stacked on the first coil inwhich power to be subjected to the power transmission is supplied at thetime of the power transmission, and power to be subjected to the powerreception is output at the time of the power reception.
 6. The powertransfer apparatus according to claim 5, wherein the first coil includesan out-in winding wire that is wound toward an inner circumference sidefrom an outer circumference side of the first coil, and an in-outwinding wire that is wound in a winding direction opposite to the out-inwinding wire toward the outer circumference side from the innercircumference side of the first coil, and in the first coil, the out-inwinding wire and the in-out winding wire are stacked such that a windingposition of the out-in winding wire is coincident with a windingposition of the in-out winding wire.
 7. The power transfer apparatusaccording to claim 5, wherein in the second coil, a second winding wireis wound a plurality of times.
 8. (canceled)
 9. A power transmissionapparatus provided in a power transfer system that includes the powertransmission apparatus and a power reception apparatus separated fromthe power transmission apparatus, and transfers power to the powerreception apparatus from the power transmission apparatus in anon-contact manner, the power transmission apparatus comprising: thepower transfer apparatus according to claim 1; and an output thatoutputs power to be transferred to the transfer of the power transferapparatus.
 10. A power reception apparatus provided in a power transfersystem that includes a power transmission apparatus and the powerreception apparatus separated from the power transmission apparatus, andtransfers power to the power reception apparatus from the powertransmission apparatus in a non-contact manner, the power receptionapparatus comprising: the power transfer apparatus according to claim 1;and an input that is connected to the transfer of the power transferapparatus.
 11. A non-contact type power transfer system, comprising: thepower transmission apparatus according to claim 9; and a power receptionapparatus that is separated from the power transmission apparatus, isdisposed to face the transfer, and configured to receive powertransmitted from the power transmission apparatus.
 12. A non-contacttype power transfer system, comprising: a power transmission apparatus;and the power reception apparatus according to claim 10 that isseparated from the power transmission apparatus and configured toreceive power transmitted from the power transmission apparatus in whichthe transfer is disposed to face the power transmission apparatus.